Various materials such as inorganic materials and organic materials are used as semiconductor materials for various parts in accordance with characteristics required. For example, inorganic insulation films such as those of silicon dioxide which are prepared by chemical gas phase deposition process, are used as layer insulation films for semiconductors. However, with recent enhancement in function and increase in performance of semiconductors, application of inorganic insulation films of silicon dioxide and the like becomes difficult due to problems such as high dielectric constant, brittleness and high water absorption rate. As one means for improving these problems, application of organic materials is being investigated.
As organic materials for semiconductors, mention may be made of polyimide resins which are superior in heat resistance, mechanical characteristics and the like, and they are used for solder resists, cover layers, liquid crystal-aligned films, and the like. However, polyimide resins generally have problems in electrical characteristics and water absorption since they have two carbonyl groups in imide ring. For the solution of these problems, it is attempted to improve electrical characteristics, water absorption and heat resistance by introducing fluorine and trifluoromethyl group into polymer molecules, but the improvement has not yet reached the desired level.
Under the circumstances, it is attempted to apply polybenzoxazole resins which are superior to polyimide resins in electrical characteristics and water absorption, to insulation materials to be used for semiconductors. It is easy for polybenzoxazole resins to satisfy only one of electrical characteristics, thermal characteristics or physical characteristics. For example, a polybenzoxazole resin made from 4,4'-diamino-3,3'-dihydroxybiphenyl and terephthalic acid has much superior heat resistance such as high heat decomposition resistance or high Tg, but is not so good in electrical characteristics such as dielectric constant and dielectric loss tangent. A polybenzoxazole resin made from 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and terephthalic acid shows good electrical characteristics such as low dielectric constant, but is not so good in heat resistance and the like. Thus, at present, there have been obtained no resins which are excellent in all of electrical characteristics, thermal characteristics and physical characteristics.